The Supreme Court’s recent ruling overturning the warrantless use of GPS tracking devices has caused a “sea change” inside the U.S. Justice Department, according to FBI General Counsel Andrew Weissmann.

Mr. Weissmann, speaking at a University of San Francisco conference called “Big Brother in the 21st Century” on Friday, said that the court ruling prompted the FBI to turn off about 3,000 GPS tracking devices that were in use.

These devices were often stuck underneath cars to track the movements of the car owners. In U.S. v. Jones, the Supreme Court ruled that using a device to track a car owner without a search warrant violated the law.

After the ruling, the FBI had a problem collecting the devices that it had turned off, Mr. Weissmann said. In some cases, he said, the FBI sought court orders to obtain permission to turn the devices on briefly – only in order to locate and retrieve them.